One approach to finding a cure for diabetes is to replace the patient's beta cells which no longer produce sufficient insulin with functionally active beta cells. Recently, techniques have been devised which enable the separation, concentration and culture of individual Islets of Langerhans. Such isolated islets are capable of reversing alloxan-induced diabetes in experimental animal systems. This technique has yet to be successful between animals of different strains, due to immunological rejection of the transplanted tissue. One method of circumventing the problem of immunological rejection is to establish a "tissue bank" of isolated islets; then, appropriate cross-matching techniques could dramatically increase the probability of a successful transplant. This study will attempt to devise methods of freezing isolated islets and isolated beta cells to explore the feasibility of long term banking of such tissue. The frozen-thawed islets and isolated beta cells will be examined for morphological appearance and assayed for insulin production, ability to grow in organ culture and ability to reverse alloxan-induced diabetes as a criteria for survival.